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Show 1899.] AMERICAN SPADE-FOOT. 793 Vertebral column twice as long as the skull. Vertebrae pro-ccelous ; neural arches covering each other, with a low crest and a short posterior process ; the three anterior diapophyses long, the first directed forwards, the second horizontal, the third directed backwards ; the following diapophyses short, the sixth and seventh slightly oblique, directed forwards. Sacral vertebra wdth strongly dilated diapophyses, which are subtriangular and a little broader than long. LTrostyle as long as the seven anterior vertebrae and fused with the sacral. Coracoids and praecoracoids strongly curved, connected by an arched cartilage ; praacoracoid not entering glenoid cavity; no omosternum; sternum a large cartilaginous plate. Suprascapular nearly entirely ossified. Humerus once and a half as long as radius-ulna. Seven bones in carpus, three in contact with radius-ulna; two bones to the pollex. Pelvis three-fourths the length of the vertebral column. Pubis cartilaginous. Femur feebly curved, longer than tibia, which is twice as long as astragalus and calcaneum. Three small bones in second row of tarsus, and a very large praehallux formed of two bones. Distal phalanges obtuse. Length of skull Badius-ulna Manus Femur Tibia Tarsus Pes millim. 20 26 41 18 12 14 30 24 20 10 22 The result of this examination of the osteological characters is that, as pointed out by Gill, Cope was quite mistaken in placing Scaphiopus together with Pelobates in a group opposed to that containing Pelodytes. In spite of a certain resemblance due to convergence through similarity in their mode of life, Scaphiopus shows no very near affinity to Pelobates, and the relation of the latter to Pelodytes is unquestionably much closer. On the other hand, the propriety of uniting the three genera in one natural group (Pelobatidce) is fully confirmed, as are, in fact, most of the groupings into higher groups proposed by the illustrious American naturalist in dealing with the classification of the Tailless Batrachians in 1865. EXPLANATION OF PLATE LII. Scaphiopus solitarius, drawn from life in three attitudes. |